The present invention is an elevator installation with a buffer for creating a zone of protection. A method of creating a zone of protection is a further subject of the invention.
Elevator installations are usually provided with one or more buffers which are arranged at the shaft floor of an elevator shaft in order to stop the elevator car when overrunning the lowermost stopping position in the elevator shaft in the downward direction and/or when overrunning the uppermost stopping position in the elevator shaft in the upward direction after transit of a predetermined travel path. This buffer is usually seated below the elevator car and/or the counterweight.
In order to prevent overrunning of an uppermost stopping position in the elevator shaft in the upward direction at the latest after transiting a predetermined travel path, buffers can also be arranged at the shaft head above the elevator car. Due to the fact that such buffers have to be arranged at the shaft floor or shaft head directly below or above the elevator car, a specific space requirement results. The shaft head or the shaft floor can therefore only be conditionally utilized for other purposes. In the case of elevator installations without a shaft pit, such a standard arrangement of a buffer is not possible, since little space is present underneath the elevator car.
An elevator installation with an elevator shaft, a vertically movable elevator car with a counterweight and with buffers is described in PCT Patent Application WO 00/64798-A1, wherein the buffer is disposed not below the elevator car, but near the elevator car at the shaft floor. The elevator car is provided with brackets which impinge on the buffer if an overrun situation arises, i.e. if the elevator car goes beyond the lowermost stopping position at the lowermost floor in the downward direction. The elevator car is thereby braked and stopped in a short distance above the shaft floor. An overrun protection against overrunning the uppermost stopping position of the elevator car in the upward direction is not proposed in this PCT patent application. The elevator installation has a shaft without a pit. A possibility of creating temporary zones of protection for carrying out maintenance and repair operations in the elevator shaft at the shaft floor and/or at the shaft head is not disclosed.
There is frequently too little space due to constructional or other reasons for a conventional elevator installation with a shaft pit and a shaft head. It may be observed that elevator shafts without an elevator pit and without an elevator head are used particularly in the case of subsequent installation or addition of an elevator installation in an already existing building. In the case of elevator shafts of that kind, but also in the case of conventional elevator shafts, there are situations in which it is necessary to create a zone of protection at the upper or lower shaft end. This is so, for example, when the elevator installation has to be maintained or checked and when for this purpose an engineer has to go into the shaft.
It is important that a system for creating such a temporary zone of protection is safe. There are different proposed solutions for that purpose. The costs and the space requirement for such a system are a further criterion. In addition, a simple checking and maintenance of the system for creating a temporary zone of protection is important. The cost in assembly and the initial aligning of all parts of such a system are also a further criterion which has to be taken into consideration.
An elevator installation with an elevator shaft and a vertically movable elevator car with counterweight is described in European Patent Application EP 0 725 033-A1. Provided at the shaft base is a touch-down device which comprises a pivotable buffer able to be pivoted into the travel path of the elevator car. A zone of protection at the shaft base can thereby be created if needed. As a special form of embodiment there is proposed a combination of a shaft buffer, which is set up outside a path of an elevator car, with a rigid pivot lever pivotable into the path of the elevator car. The elevator car when hitting the pivot lever can thus be braked by the shaft buffer and supported above the shaft floor at a height which lies above the lowermost stopping position of the elevator car.
It is a disadvantage of this form of embodiment that it is indeed suitable for creating a zone of protection at the shaft floor, but does not offer any possibility of stopping overrunning of the lowermost stopping position of the elevator car in the elevator shaft in the downward direction after transiting a predetermined travel path. A possibility of creating a zone of protection at the shaft head is also not provided.
An elevator installation with an elevator shaft, a vertically movable elevator car with a counterweight and a movable support device is described in PCT Patent Application WO 02/051737-A1. The support device is arranged eccentrically at the shaft base between the elevator car and the counterweight and can be moved into the path of the elevator car when necessary. The support device comprises a plate which is pivotably articulated to the shaft floor. If required, this plate is simply pivoted in the direction of the elevator car. Disposed at the elevator car is a buffer which impinges on the plate and stops the elevator car at a predetermined spacing from the shaft floor. A zone of protection at the shaft floor can thereby be created in the case of need. In order to be able to create a zone of protection in the region of the shaft head the elevator car comprises, according to the PCT patent application, a device which is fastened to the roof of the elevator car. This device can be pivoted up and moves against the shaft roof. A zone of protection is thus created at the upper end of the shaft. This PCT patent application is considered to the closest state of the art.
It is a disadvantage of this form of embodiment that for creating a zone of protection at the shaft head there is needed a device which is seated on the elevator car. The mass to be accelerated and moved is thereby increased.